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SHEET METAL PULLEY AND DRUIVL Patented Oct. 2

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NORMAN MAOBETH, OF BOLTON LE MOORS, COUNTY OF LANCASTER,

ENGLAND.

SHEET-METAL PULLEY AND DRUM.

SPECIFICATION forming part of Letters Patent No. 286,028, dated October 2, 1883,

Application filed August 24, 1883. (N0 model.) Patented in England June 18, 1881, No. 2,675.

To all whom it may concern:

Be 11: known that I, NOR-MAN MAoBErI-i, a

subject of the Queen of Great Britain and Ireland, and residing at Bolton 1e Moors, in the county of Lancaster, England, have invented a certain Improvement in Sheet-Metal Pulleys and Drums, (for which I have obtained a patent in Great Britain, No. 2,675, June 18, $881,) of which the following is a specifica- My invention relates to the pulleys and drums used in the transmission of rotary motion, having sheet-metal rims riveted to metal arms, and has for its object to obtain a more secure connection between the rim and the arms. In the ordinarymethod of manufacture a hole is punched or drilled in the metal of the rim, and this hole is countersunk to provide for the formation of a head upon the rivet; but as this head is only about equal in depth to the thickness of the metal of the rim, the attachment is not secure, and there is a tendency for the rim to break away. In my invention I form a countersunk cavity or de pression in the end of the arm, and I press the metal of the rim into this cavity in the operation of punching, or by a subsequent operation, whereby I obtain a deep conical cavity or depression in the metal of the rim,

which, when filled by the rivet-head, or by.

the riveting over of the end of the rivet, in-

' sures a firm hold of the rivet upon the rim, so

that the latter cannot break away.

In the accompanying drawings, Figure 1 is sectional view of part of the rim of a pulley showing the end of one arm and one rivet.

Fig. 2 shows the kind of punch employed.

The end of the arm a, which is secured to the inner surface of the 'rim 1), is formed with 40 a countersunk cavity, 0, preferably of a conical form. The projecting end of the arm,with the rim in position, is brought beneath a punch in a suitable punching machine or press, the said projecting end being supported by a suitable bed to resist the pressure of the punch. When the punch descends, the metal of the rim is forced into the cavity in the end of the arm, whereby a conical cavity is formed in the metal of the rim, as clearly indicated in the drawings. The punch shown in Fig. 2 is suitable to be used in the operation of pressing the rim into the cavity in the arm end, and also punches the hole for the rivet; but this hole may have been previously punched or formed. WVhen the rivet d is riveted or head ed up, the rim becomes much more firmly secured than in the ordinary method of formation, as the conical head at of the rivet may be several times the thickness or depth of the rim, and has a firm hold of the cone formed on the rim, which cone is tightly nipped between the rivet and the arm. The rivet can be finished off perfectly flush with the surface of the rim without rendering the fastening insecure, even when a very thin rim is used. The conical part of the rivet may be the head formed on the rivet previously to its use, or may be the part headed up in the riveting operation, or, in some cases, abolt with a conical head may take the place of the rivet. Only one form of arm is illustrated, but it will be understood that in some forms of arms more than one rivet may be used.

I claim as my invention 1. In pulleys and drums having sheet-metal rims, the countersunk cavity in the end of the arm, and the metal rim punched or pressed into such cavity, so as to form a countersunk cavity for the rivetvor bolt deeper than the thickness of the rim, substantially as set forth. I

2. In fastening the arms of pulleys and drums to the sheet-metal rims, the conical cavity 0 in the arm end, the inwardly-projecting cone formed on the rim by pressing it into the said cavity, and the rivet filling the conical cavity in the rim and holding the parts together, substantially as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

NORMAN MAOBETH. 

